1. Technical Field
The present invention relates to a disk drive and, more particularly, to a disk drive provided with a latching mechanism for latching an actuator.
2. Description of the Related Art
A recent hard disk drive employs a head slider moving mechanism for moving a head slider supporting a magnetic head to prevent the head slider from sticking to the surface of a magnetic disk and to improve the reliability thereof in withstanding shocks applied thereto. The head slider moving mechanism holds an actuator on a part called a ramp disposed near the circumference of the magnetic disk to keep the head slider apart from the surface of the magnetic disk while the hard disk drive is not in operation.
FIG. 16 shows, by way of example, a hard disk drive 1 provided with a head slider moving mechanism. The hard disk drive 1 shown in FIG. 16 has a disk pack (case) 3 including a base 2 having the shape of a bottomed box, and a cover, not shown, for covering an open upper side of the base 2. A predetermined number of magnetic disks 4 are mounted in layers on a spindle motor, not shown, of in-hub construction so as to be rotatable. The spindle motor is disposed on the side of the base. The magnetic disks 4 are rotated at a predetermined rotating speed by the spindle motor.
An actuator 10 is disposed in the disk pack 3. FIG. 17 is a top view of the magnetic disk 4 and the actuator 10. Referring to FIGS. 16 and 17, the actuator 10 has a head support arm 12 supported by the middle part thereof on a pivot (shaft) 11 for rotation relative to the base 2. A head slider 14 holding a magnetic head 13 for reading recorded data from the magnetic disk 4 and writing data to the magnetic disk 4 is attached to a front end part of the head support arm 12. A voice coil 15 is held on a back end part of the head support arm 12. The voce coil 15 is disposed between a coil holding arms 16a and 16b that extend in a V-shape from a part around the pivot 11 of the head support arm 12 so as to diverge from each other.
A stator 17 is disposed on the base 2. The stator 17 creates a magnetic field in a space between the voice coil 15 held on the back end part of the actuator 10, and the stator 17. Thus, the voice coil 15 and the stator 17 constitute a voice coil motor (VCM) for turning the actuator 10. The VCM drives the actuator 10 for turning on the pivot 11 to move the magnetic head 13 attached to the front end part of the actuator 10 substantially along a radius of the magnetic disk 4 for a seek operation so that the magnetic head 13 can be located opposite to a desired track on the magnetic disk 4.
A ramp 18 is held on the base 2 to hold the head slider 14 holding the magnetic head 13 apart from the magnetic disk 4 while the hard disk drive 1 is not in operation.
An inertial latching mechanism 20 is attached to the base 2. The inertial latching mechanism 20 latches the actuator 10 when an intense shock is applied to the hard disk drive 1 by an inertial force resulting from the shock acting on the hard disk drive 1. FIG. 18 is an enlarged view of the inertial latching mechanism 20 and the associated parts. As shown in FIGS. 17 and 18, the inertial latching mechanism 20 has a latching arm 22 having a middle part supported by a pivot (shaft) 21 on the base 2 (FIG. 16). The latching arm 22 is able to turn on the pivot 21. A projection 23 projects from the front end of the latching arm 22 into the base 2, i.e., into the paper as viewed in FIG. 18. A pin 24 is attached to a back end part of the latching arm 22 so as to extend away from the bottom of the base 2, i.e., out of the paper as viewed in FIG. 18. An inertial arm, not shown, is disposed near the pin 24. The inertial arm is turned by an external shock so as to push the pin 24.
When the hard disk drive 1 is not operating for reading data from or writing data to the magnetic disk 4, the VCM drives the actuator 10 to set the head slider 14 on the ramp 18. If a relatively small shock is applied to the hard disk drive 1 in this state, the ramp 18 restrains the head slider from movement so that the head slider 14 may not move toward the magnetic disk 4. If a relatively large shock is applied to the hard disk drive 1, the inertial arm, not shown, pushes the pin 24 to turn the latching arm 22 in the direction of the arrow α. Consequently, the projection 23 is engaged with inner side, near the extremity of the coil holding arm 16a, of a part 161 to latch the actuator 10. The inertial latching mechanism 20 thus restrains the movement of the head slider 14 so that the head slider 14 may not move toward the magnetic disk 4.
In FIGS. 17 and 18, the actuator 10 holding the head slider 14 is restrained from movement by the inertial latching mechanism 20. In the normal state, the latching arm 22 of the inertial latching mechanism 20 is pulled in the direction of the arrow β by a spring, not shown, to keep the projection 23 disengaged from the coil holding arm 16a. 